Recombinant M. Smegmatis Controls for Safe Pathogen Assay Verification
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Solution Overview
Problem
Current diagnostic methods for tuberculosis and methicillin-resistant Staphylococcus aureus are hindered by the need for costly, hazardous, and time-consuming production of live bacterial strains for calibration, posing risks and inefficiencies in accuracy and scalability.
Innovation Solution
Development of recombinant Mycobacterium smegmatis strains with modified genomes containing nucleic acids from Mycobacterium tuberculosis or Staphylococcus aureus, mimicking the diagnostic profiles of these pathogens, allowing safe and efficient production of verification standards for molecular diagnostic assays.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If live bacterial strains are used for calibration standards in molecular diagnostic assays, then diagnostic accuracy can be verified, but biohazard risks increase and production becomes hazardous and costly
Solution Approach 1:
The patent creates recombinant Mycobacterium smegmatis strains that contain specific nucleic acid sequences from M. tuberculosis (such as the RRDR region) or S. aureus (such as the SCCmec element). These recombinant strains serve as safe copies that mimic the diagnostic profiles of the pathogenic organisms, allowing verification of molecular diagnostic assays without using live pathogenic bacteria. The copying principle resolves the contradiction by providing a non-hazardous alternative that maintains diagnostic reliability.
2Reliability
If live bacterial strains are produced for calibration standards, then diagnostic verification is possible, but production time and cost increase
Solution Approach 1:
The recombinant M. smegmatis strains can be produced more rapidly than traditional methods requiring cultivation and subsequent inactivation of pathogenic bacteria. The copying approach allows for faster generation of calibration standards through recombinant DNA technology, reducing the time loss while maintaining diagnostic verification capability.
Solution Approach 2:
The patent employs a disposable, non-pathogenic bacterial host (M. smegmatis) that can be rapidly cultured and discarded after use as a calibration standard. This approach eliminates the need for complex, expensive, and time-consuming processes of producing and safely managing live pathogenic strains, thereby reducing both time and cost while maintaining reliability.
3Measurement precision
If pathogenic bacteria are used as calibration standards, then diagnostic profile accuracy is maintained, but safety and scalability are compromised
Solution Approach 1:
The recombinant M. smegmatis strains are engineered to contain specific nucleic acid sequences that are detected by the same molecular diagnostic assays used for pathogenic organisms. For example, the recombinant strain contains the SCCmec junction region that is detected by the same probe used for MRSA detection. This copying approach maintains measurement precision while enabling safe scalability.
Solution Approach 2:
The patent changes the biological safety parameters by replacing pathogenic bacteria with non-pathogenic M. smegmatis while maintaining the diagnostic-relevant nucleic acid sequences. This parameter change allows the calibration standards to be scaled up production without the safety constraints that limit the scalability of pathogenic organism-based standards.
Data Source
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AI summary
The present invention relates to a recombinant bacterium based on a non-pathogenic bacterium that has a modified genome containing a nucleic acid of interest from a pathogen that is detected by a molecular diagnostic assay and that mimics the diagnostic profile of the pathogen. The invention further relates to a diagnostic control composition comprising the recombinant bacterium and to methods for producing the recombinant bacterium. The recombinant bacterium is a safe, reliable quality control for the detection of pathogens such as Mycobacterium tuberculosis and Staphylococcus aureus. The invention also relates to a kit comprising either the recombinant bacterium, compositions containing the recombinant bacterium or bacteria produced according to the method of the invention.